Earless clamp structure

ABSTRACT

A clamp structure especially for use in applications in which space conditions do not permit any projecting parts such as plastically deformable ears, and in which outwardly extending hooks adapted to engage in apertures are used to mechanically interconnect the clamp structure; to enable tightening of the band about an object to the fastened, cold-deformed pressed-out embossments are provided in inner and outer band portions, which extend generally in the circumferential direction so that each pressed-out embossment remains integral at least on both sides thereof, where the tool-engaging surfaces thereof are able to withstand very large tightening forces in the circumferential direction which permit a secure tightening of the clamp structure.

The present invention relates to a clamp structure and more particularlyto a clamp structure for use in applications in which space conditionsdo not permit any projecting parts such as plastically deformable earsor tightening devices for contracting the clamp structure about anobject to be fastened.

BACKGROUND OF THE INVENTION

Plastically deformable ears of the type which have become known as"Oetiker" ears have been used heretofore with great success in a varietyof clamp structures. Among these clamp structures, one mustdifferentiate between so-called endless clamp structures and open clampstructures which can be closed when installed about the object to befastened. While the former permit only an axial installment, the latterpermit axial as well as radial installment. My prior U.S. Pat. Nos.2,614,304 and 3,082,498 are representative of the former type of clampswhile my prior U.S. Pat. Nos. 3,465,793; 3,523,337 and 3,510,918 arerepresentative of the latter type. Additionally, known in the prior artare hose clamps with so-called screw-type tightening devices in whichthe band ends are drawn together by rotating a screw. However, all ofthese aforementioned types of clamps entail the drawback that theyinclude outwardly projecting parts that in certain applications precludeuse of such types of clamps.

More specifically, clamps used with axle boots in the automotiveindustry, in certain applications, must be devoid of any projectingparts because of space requirements. As a result thereof, closed copperrings were used heretofore in the automotive industry which were shrunkonto the axle boots by the use of "Magnaform" machines. Apart from thehigh capital expenditures for the machinery necessary to perform themagnetic shrinking operation on metal rings, such as steel or copperrings, this approach inherently involves certain limitations since thecopper rings can be installed only axially. Moreover, for serviceoperations, it is necessary, in case the copper ring is still intact, todestruct the copper ring to gain access to the space underneath the axleboot which would then require the axial installation of a new copperring to be shrunk over the axle boot. Since the machines necessary forshrinking the copper rings over the axle boots are normally notavailable at the service organization of a retail dealer in view of thehigh costs connected therewith, it has been common practice to stockpreassembled axle parts with copper rings already shrunk onto the axleboots for exchange with corresponding parts in a vehicle requiringservice. This complicated and costly approach in servicing axles withaxle boots secured by shrunk copper rings was thus also due to the lackof re-useability of the copper ring.

Object of the Invention

Accordingly, it is a principal object of the present invention toprovide a clamp structure which can be used in applications in whichspace conditions do not permit any projecting parts and which avoids bysimple means the aforementioned shortcomings and drawbacks encounteredin the prior art.

The underlying problems are solved according to the present invention inthat a clamp structure having open ends is mechanically interconnectedat the open ends and is provided with tool-engaging embossments in innerand outer band portions which are formed by cold-deformed, pressed-outportions generally in the circumferential direction so that eachpressed-out portion remains integral at least on both sides thereof withthe respective remaining band portion. As a result thereof, tighteningforces of several hundred kg can be readily applied by the use of a toolso that the clamp structure can be securely tightened about the objectto be fastened without the use of any other tightening means in theclamp structure itself.

According to another feature of the present invention, the outer bandportion is provided adjacent its pressed-out tool-engaging embossmentwith an elongated opening of such width that the pressed-outtool-engaging embossment of the inner band portion can extendtherethrough. The tool-engaging embossments of the inner and outer bandportions are thereby preferably of complementary shape so that the innerpressed-out tool-engaging embossment is able to slide underneath theouter pressed-out tool-engaging embossment during the tightening of theclamp structure whereby lateral movement of the inner band portionrelative to the outer band portion in the axial direction of the clampstructure is prevented.

According to still another feature of the present invention, the innerband portion may be provided with an outwardly extending hook spacedfrom the pressed-out tool-engaging embossment by such a distance thatthe hook, when extending through the opening, will permit a pre-assemblywhen engaging with the end surface of the opening opposite thetool-engaging embossment in the outer band portion.

In a preferred embodiment of the present invention, the cold-deformedpressed-out tool-engaging embossments have an at least approximatelycircularly shaped configuration in axial cross section through the clampstructure so that each pressed-out portion is integral with therespective inner and outer band portion at least along the two sidesthereof.

According to still a further feature of the present invention, the innerand outer band portions are provided with further means effectivelyeliminating any step in the area of overlap thereof, which is formed bya tongue-like extension at the free end of the inner band portionoperable to engage in a tongue-receiving opening or channel formed by anoutwardly directed step in the outer band portion on the side of itstool-engaging embossment opposite the opening. In a particularly simpleconstruction, only one outwardly extending cold-deformed hook with anengaging and abutment surfaces performing both guide and supportfunctions which extends out of the plane of the inner band portion whilebeing integral therewith over at least a substantial part of itsremaining contour, provides by its engagement in a correspondingaperture the mechanical connection between the inner and outer bandportions. The engaging and abutment surfaces of this cold-deformed hookare thereby approximately V-shaped, as seen in plan view.

If the inner and outer band portions are standard parts and are adaptedto be mechanically connected with a clamping band of suitable length,then it is possible to produce a clamp structure of any desireddiametric dimension by merely cutting the band to suitable length andpunching out apertures near the two ends thereof for engagement with thehooks in the corresponding part of the inner and outer band portions.This permits a simple "do-it-yourself" approach requiring only twostandard parts and a supply of clamping bands adapted to be cut andprepared by a tool designed therefor.

These and other objects, features and advantages of the presentinvention will become more apparent from the following description whentaken in connection with the accompanying drawing, which shows, forpurposes of illustration only, several embodiments in accordance withthe present invention, and wherein:

FIG. 1 is a perspective view of an earless clamp structure in accordancewith the present invention;

FIG. 2 is a cross-sectional view taken along line II--II of FIG. 1;

FIG 3 is a cross-sectional view taken along line III--III of FIG. 1;

FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. 1;

FIG. 5 is a plan view on the area of the mechanical interconnection ofthe earless clamp structure illustrated in FIG. 1 with the two endsthereof mechanically interconnected;

FIG. 6 is a cross-sectional view taken along line VI--VI of FIG. 5;

FIG. 7 is a cross-sectional view taken along line VII--VII of FIG. 5;

FIG. 8 is an axial elevational view on a part of the clamp structure ofFIG. 1, indicating the manner of installation by the use of a clampingtool;

FIG. 9 is a plan view on a modified embodiment of a clamp structure inaccordance with the present invention, in which the inner band portionis provided with two support hooks as well as with an additionalcold-deformed hook performing both guide and support functions;

FIG. 10 is an elevational view of the part of the clamp structureillustrated in FIG. 9;

FIG. 11 is a plan view on a part of a still further modified embodimentof a clamp structure in accordance with the present invention, in whichthe inner band portion is provided with two support hooks and a furtherhook performing both guide and support functions;

FIG. 12 is an elevational view of the part of the clamp structureillustrated in FIG. 11;

FIG. 13 is a plan view on a modified embodiment of an earlessthree-partite clamp structure in accordance with the present inventionconsisting of two standard parts and of a clamping band;

FIG. 14 is an elevational view of the parts of the clamp structureillustrated in FIG. 13;

FIG. 15 is a plan view on the clamp structure of FIG. 13 showing the twostandard parts assembled to the clamping band while the two standardparts are not yet mechanically interconnected;

FIG. 16 is an elevational view of the clamp structure of FIG. 15.

FIG. 17 is a plan view on the three-partite clamp structure of FIGS. 13through 16 showing all the parts thereof in the assembled condition; and

FIG. 18 is an elevational view of the assembled clamp structure of FIG.17.

Referring now to the drawings wherein like reference numerals are usedthroughout the various views to designate like parts, and moreparticularly to FIGS. 1-8, reference numeral 10 generally designates inFIG. 1 an earless clamp structure which includes a clamping band 11having open ends adapted to be mechanically interconnected. Themechanical interconnection is effected by an outwardly extending guidehook 12 and two support hooks 13 provided on the inner band portion 14which are adapted to engage in apertures 15 provided in the outer bandportion 16. The guide and support hooks 12 and 13 may thereby beconstructed as disclosed in my prior U.S. Pat. No. 4,299,012.

To enable tightening of the clamp structure about an object to befastened by the use of a tightening tool generally designated byreference numeral 20 (FIG. 8) and having mutually facing end portions 21and 21' provided at the end of the jaws 22 and 22' of the pincer-liketightening tool 20, the outer and inner band portions are each providedwith a tool-engaging abutment 24 and 25, respectively, in the form ofcold-deformed pressed-out embossments of at least approximatelysemi-circularly shaped cross section (FIGS. 3 and 4). The pressed-outtool-engaging embossment 24 in the outer band portion 16 is therebyessentially semi-cylindrical with transverse abutment surfaces 24a and24b while its cylindrical walls in the axial direction are integral withthe outer band portion 16. The cold-deformed pressed-out tool-engagingembossment 25 of the inner band portion 14, in contrast thereto, hasonly one tool-engaging abutment surface 25a while being integral withthe inner band portion 14 substantially over its remaining contour. Theouter band portion 16 is also provided with an elongated slot or opening27 between its pressed-out embossment 24 and the apertures 15 which isof such width that the pressed-out tool-engaging abutment 25 of theinner band portion 14 can extend therethrough. Moreover, the inner andouter pressed-out embossments 25 and 24 are thereby of complementaryshape (FIG. 7) so that the pressed-out embossment 25 of the inner bandportion 14 can slide underneath the pressed-out embossment 24 of theouter band portion 16 during tightening of the clamp by means of thetightening tool 20.

To enable a sort of pre-assembly, a further outwardly extending hook 28is provided in the inner band portion 14 adjacent the pressed-outembossment 25 which is also adapted to extend through the opening 27 andprovide pre-assembly when coming into abutment with the end face 27a ofthe opening 27. The hook 28 may thereby be a simple punched-out hook oftab-like configuration.

Since it becomes increasingly important with the thinner and harderplastic hose materials to avoid any step or discontinuity along theinner object-engaging surfaces of the clamp structure, the clampstructure in accordance with the present invention is provided withfurther means which eliminates any step. These means are similar to themeans disclosed in my prior U.S. Pat. No. 4,299,012 and U.S. Pat. No.4,315,348 and include a tongue-like extension 31 at the free end of theinner band portion 14 which is adapted to engage in a tongue-receivingchannel 32 (FIG. 2) formed by a step 33 and two longitudinal cuts 34 and34' which permit the formation of the channel 32 by pressing out thecentral band portion 35 relative to the lateral band portions 36remaining on both sides of the cuts 34 and 34'. As described more fullyin my aforementioned two patents, in the assembled condition (FIG. 8),the tongue-like extension 31 will engage in channel 32 so that any stepis effectively eliminated thereby. The means for eliminating any step ordiscontinuity may of course also be modified as disclosed in myaforementioned prior patents.

FIG. 9 illustrates a preferred embodiment in accordance with the presentinvention in which the guide hook 12 of the embodiment of FIGS. 1-8 isreplaced by a cold-deformed hook 112 performing both guide and supportfunctions. This hook 112 is thereby cold-deformed out of the inner bandmaterial 14 in such a manner that it is separated from the inner bandportion 14 only along the guide and abutment surfaces 112a and 112bwhich are substantially V-shaped as viewed in plan view in FIG. 9. Alongthe rest of its contour, the cold-deformed hook 112 is integral with theinner band portion.

In the embodiment of FIGS. 11 and 12, the guide hook 12 of theembodiment of FIGS. 1-8 is replaced by a guide and support hook 212which is of tab-like configuration, pressed-out of the band material andextending generally in the circumferential direction, which is providedwith a guide surface 212a, much in the manner of the tab 4 of my priorU.S. Pat. No. 3,286,314.

The modified embodiment of an earless clamp structure illustrated inFIGS. 13 through 18, in which similar reference numerals of the 100series are used to designate parts corresponding to those of the clampstructure of FIGS. 1 through 12, consists of three parts, namely aclamping band 11 and of two connecting parts generally designated byreference numerals 114 and 116 formed by corresponding band portions.The open ends of the clamping band 111 are thereby adapted to bemechanically connected with a respective band portion 114 and 116 whilethe latter are adapted to be mechanically interconnected in a mannersimilar to the mechanical interconnection described in connection withthe embodiment of FIGS. 1 through 12. More specifically, the band part116 is mechanically connected with the clamping band 111 by means of aguide hook 112' and two support hooks 113 provided on the part 116 whichare adapted to engage in aperture 117 provided near one end of theclamping band 111. Similarly, the band part 114 is adapted to bemechanically connected with the opposite end of the clamping band bymeans of a guide hook 112' and two support hooks 113 adapted to engagein apertures 117, in the manner more fully disclosed in my prior U.S.Pat. No. 4,299,012. To permit preassembly, a further approximatelyL-shaped hook 118 is provided on each of the band parts 114 and 116(FIGS. 13 and 14), which is adapted to be bent over the correspondingend of the clamping band 111, as shown in FIGS. 15 and 16 in order tohold the parts 114 and 116 fixed in position relative to the clampingband 111.

To enable tightening of the clamp structure about the object to befastened by the use of a tightening tool, similar to the tool 20illustrated in FIG. 8, the band portions 116 and 114 are each providedwith a tool-engaging abutment 124 and 125, respectively, constituted bycold-deformed, pressed-out embossments of at least approximatelysemi-circularly shape in cross-section, whereby the pressed-out toolengaging embossment 124 in the band portion 116 is essentiallysemi-cylindrical with transverse abutment surfaces 124a and 124b whileits longitudinal cylindrical walls are integral with the outer bandportion 116. In contrast thereto, the cold deformed pressed-out toolengaging embossment 125 of the band portion 114 only has one toolengaging abutment surface 125a while being integral with the bandportion 114 substantially over its remaining contour.

The band portion 116 is again provided with an elongated opening 127which is of such width that the pressed out tool engaging abutment 125of the band portion 114 can extend therethrough. An outwardly extendinghook 128 is also provided again in the band portion 114 adjacent thepressed-out embossment 125, which is adapted to extend through theopening 127 in order to provide a preassembly when in abutment with theend face 127a of the opening 127. Moreover, the inner and outer pressedout embossments 125 and 124 are again of complementary shape as shown inFIG. 7, so that the pressed out embossment 125 of the inner band portion114 can slide underneath the pressed out embossment 124 of the outerband portion 116 during tightening of the clamp structure by thetightening tool.

The mechanical interlock between the band portions 114 and 116 isthereby effected by a cold-deformed pressed-out hook 112 similar to thehook 112 of FIG. 9 which performs both guide and support functions andto that end is of approximately V-shaped configuration with inclinedsurfaces 112a and 112b as seen in plan view (FIG. 13). The guide andsupport hook 112 which is adapted to engage in aperture 115a provided inthe band portion 116, due to its particular configuration andconstruction, is thereby sufficient to withstand the substantialtightening forces required for installing the clamp structure withoutthe use of an ear or the like, which forces may attain, depending onthickness and width of the band, a magnitude of up to 500 kg and more toobtain a clamp structure that seals completely satisfactorily.

To avoid any step or discontinuity along the entire inner objectengaging surfaces of the clamp structure, the clamp structure inaccordance with the present invention, illustrated in FIGS. 13 through18, is provided with further means which eliminated any steps in thearea of overlap between the band portion 114 and the band portion 116,between the band portion 114 and one end of the clamping band 111 andbetween the band portion 116 and the opposite end of the clamping band111. More specifically, to avoid any such step between the band portions114 and 116, the band portion 114 is again provided with a tongue-likeextension 131 adapted to engage in a tongue receiving channel formed bythe step 133 and the longitudinal cuts 134 which permit the formation ofthe tongue receiving channel by pressing out the central part 135,having lateral band portions 136 on both sides thereof.

To avoid a step in the area of overlap between the two ends of theclamping band 111 and the band portions 114 and 116, the latter are eachprovided with a tongue-like extension 137 adapted to engage in aperture138 on the side of the step 139 opposite the apertures 117. These meansare again similar to the means disclosed in my prior U.S. Pat. No.4,299,012 and 4,315,348.

The clamp structure of FIGS. 13 through 18 offers the additionaladvantage that it permits the attainment of a clamp structure of anydesired diameter by utilizing a "do-it-yourself" approach, so to speakof. For that purpose, it is only necessary to stock as standard partsthe band portions 114 and 116 and a roll of clamping band 111, tothereupon cut the clamping band to predetermined length and to formapertures 117 and 138 therein by the use of a tool, such as for exampledescribed in my prior U.S. Pat. No. 4,050,154, which may also bemodified to produce the step 139. By thus utilizing a three-partiteclamp structure consisting of two standard parts, it is possible tomake, on the spot, a clamp structure of desired dimensions, utilizingfor example, a table indicating the length of the clamping band whichmust be cut off for a given diametric dimension, when using thestandardized parts 114 and 116.

While I have shown and described several embodiments in accordance withthe present invention, it is understood that the same is not limitedthereto but is susceptible of numerous changes and modifications asknown to those skilled in the art and I therefore do not wish to belimited to the details shown and described herein but intend to coverall such changes and modifications as are encompassed by the scope ofthe appended claims.

I claim:
 1. A clamp structure, especially for use in applications inwhich space conditions do not permit any projecting parts, such asplastically deformable ears, comprising clamping band means having openends formed by an inner and outer band portion intended to overlap, andmeans mechanically interconnecting the overlapping open ends of the bandmeans including outwardly extending hook means in the inner band portionoperable to engage in aperture means in the outer band portion in theinstalled condition of the clamp structure, characterized in that themeans mechanically interconnecting the open ends enable tightening ofthe band means about an object to be fastened and include tool-engagingmeans provided in the inner and outer band portions, said tool-engagingmeans being formed by pressed-out portions pressed-out of the inner andouter band portions and extending generally in the circumferentialdirection so that each pressed-out portion remains integral at least onboth sides thereof with the respective band portion, whereby saidtool-engaging means are able to withstand substantial forces in thecircumferential direction without tearing which permit a securetightening of the clamp structure about the object to be fastenedwithout the use of any other tightening means in the clampstructure.Iadd., and in that the tool-engaging means in the inner bandportion is located in the inner band portion on the side of the hookmeans nearer the free end of the inner band portion so that in theinstalled condition of the clamp structure it comes to lie on the sideof the aperture means opposite the free end of the outer band portion..Iaddend. .[.2. A clamp according to claim 1, characterized in that theouter band portion is provided adjacent its pressed-out tool-engagingmeans with an elongated opening extending in the direction toward theend of the outer band portion and, adjoining said opening, with aperturemeans receiving said hook means, said opening being of such width thatthe pressed-out tool-engaging means of the inner band portion can extendtherethrough..]. .[.3. A clamp structure according to claim 2,characterized in that said inner band portion is provided with anoutwardly extending hook spaced from the pressed-out tool-engaging meansthereof in the circumferential direction away from the free end thereof,said hook being of such width as to be able to extend through saidopening and upon engagement with the end surface of said openingopposite the tool-engaging means determining a pre-assembly position ofthe two tool-engaging means..]. .[.4. A clamp structure according toclaim 2, characterized in that the pressed-out tool-engaging means ofthe inner and outer band portions are of complementary shape so that theinner pressed-out tool-engaging means is able to slide under the outerpressed-out tool-engaging means during tightening of the clampstructure..].
 5. A clamp structure according to claim 4, characterizedin that the pressed-out tool-engaging means have an at leastapproximately semi-circularly shaped configuration in axial crosssection through the clamp structure near at least one end of eachpressed-out tool-engaging means to receive a pointed end of apincer-like tightening tool.
 6. A clamp structure according to claim 5,characterized in that the pressed-out tool-engaging means of the innerband portion is separated from the inner band portion by a generallytransversely extending cut but is generally integral with the inner bandportion over its remaining contour.
 7. A clamp structure according toclaim 6, characterized in that the pressed-out tool-engaging means ofthe outer band portion is separated from the outer band portion by twogenerally transversely extending .[.buts.]. .Iadd.cuts .Iaddend.but isintegral with the outer band portion along its two sides.
 8. A clampstructure according to claim 5, characterized in that the inner andouter band portions are provided with further means effectivelyeliminating any step in the area of overlap of the free end of the innerband portion and of the overlying outer band portion.
 9. A clampstructure according to claim 8, characterized in that said further meansincludes a tongue-like extension at the free end of the inner bandportion operable to engage in a tongue-receiving means formed at leastin part by an outwardly directed step in the outer band portion on theside of its tool-engaging means opposite said opening.
 10. A clampstructure according to claim 9, characterized in that saidtongue-receiving means is formed by two longitudinal cuts in the outerband portion which extend from the step away from the tool-engagingmeans, said cuts leaving a lateral object-engaging bend portion on eachside and a central band portion outwardly displaced relative to thelateral band portions and defining in effect a channel for receivingtherein said tongue-like extension.
 11. A clamp structure according toclaim 10, characterized in that at least one hook means is formed by acold-deformed hook having an engaging and abutment surface meansperforming both guide and support functions and extending out of theplane of the corresponding band portion while being integral therewithover at least a substantial part of its remaining contour.
 12. A clampstructure according to claim 11, characterized in that said engaging andabutment surface means is approximately V-shaped, as seen in plan view.13. A clamp structure according to claim 10, characterized in that saidinner and outer band portions are integral with said band means, and inthat at least one hook means is a cold-deformed support hook having aforce-engaging abutment surface extending out of the plane of the innerband portion while being integral therewith over at least a substantialpart of its remaining contour.
 14. A clamp structure according to claim13, characterized in that another hook means performs a guide functionoperable to guide the inner and outer band portions relative to oneanother during tightening of the clamp structure.
 15. A clamp structureaccording to claim 14, wherein said another hook means is a tab-likesuspension hook extension generally transversely to the circumferentialdirection and separated from the respective inner band portion by cutsalong its sides and end.
 16. A clamp structure according to claim 14,wherein said another hook means is a tab-like hook bent out of the innerband material and extending generally in the circumferential direction,said hook having an inclined end face performing a guiding function. 17.A clamp structure according to claim 14, wherein said another hook meansis formed by a cold-deformed hook having an engaging and abutmentsurface means performing both guide and support functions and extendingout of the plane of the corresponding band portion while being integraltherewith over at least a substantial part of its remaining contour. 18.A clamp structure according to claim 17, wherein said engaging andabutment surface means is of approximately V-shape, as seen in planview.
 19. A clamp structure according to claim 10, characterized in thatsaid inner and outer band portions are formed by two band portionsseparate from said band means but in overlapping relationship therewith,said two band portions being provided with said tool-engaging means andeach of said band portions being mechanically connected to a respectiveend of said band means by outwardly extending hook means engaging incorresponding aperture means.
 20. A clamp structure according to claim19, characterized in that the last-mentioned hook means are provided inthe band portions and the aperture means are provided near the ends ofthe band means.
 21. A clamp structure according to claim 20,characterized in that each band portion is provided with anapproximately L-shaped pre-assembly hook adjacent the innermost hookmeans which is operable to be bent down in the direction toward and overthe free end of the band means to hold the same in a pre-assembledcondition relative to the corresponding band portion when the hook meansof the band portion are in engagement with the aperture means of theband means.
 22. A clamp structure according to claim 20, characterizedin that the band portions and the band means are provided with furthermeans effectively eliminating any steps in the area of overlap of theband portions and the respective ends of said band means, said furthermeans including a tongue-like extension at each end of the band meansoperable to engage in a tongue-receiving means formed at least in partby an outwardly directed step in the band means.
 23. A clamp structureaccording to claim 19, characterized in that in the assembled conditionin which the clamp structure is tightened about the object to befastened, the two band portions are mechanically connected with eachother by an outwardly extending hook means in the inner band portion,which simultaneously performs both guide and support functions as itengages in an aperture means provided in the outer band portion.
 24. Aclamp structure according to claim 23, in which said last-mentioned hookmeans is a cold-deformed hook having an engaging and abutment surfacemeans that extends out of the plane of the corresponding band portionwhile being integral therewith over at least a substantial part of itsremaining contour.
 25. A clamp structure according to claim 24,characterized in that said engaging and abutment surface means isapproximately V-shaped, as seen in plan view. A clamp structureaccording to claim 25, wherein only a single cold-deformed hook engagingin one aperture means mechanically interlocks the two band portions..[.27. A clamp structure according to claim 1, wherein the tool-engagingmeans in the outer band portion is located on the side of the aperturemeans opposite the free end of the outer band portion and thetool-engaging means in the inner band portion is located between theoutwardly extending hook means and the free end of the inner bandportion..]. .[.28. A clamp structure according to claim 1, wherein theinner band portion is located exclusively radially inwardly of the outerband portion within the area of the mechanical interconnecting meansincluding the tool-engaging means..]. .[.29. A mechanical connectionaccording to claim 28, characterized in that said force engaging surfacemeans is of approximately V-shape, as seen in plan view..]. .[.30. Amechanical connection according to claim 29, characterized in that onlya single such combined guide and support hook is used in the mechanicalconnection..].
 31. A mechanical connection between two mutuallyoverlapping band portions forming part of an open clamp structureadapted to be tightened about an object to be fastened, in which atleast two outwardly extending hook means provided in the inner bandportion are operable to form-lockingly engage in an aperture meansprovided in the outer band portion, characterized in that at least onehook means is a cold-deformed support hook having a force-engagingsurface means and another hook means is a combined guide and supporthook having a force-engaging surface means operable to initially guidethe inner and outer band portions toward one another and to absorbcircumferentially directed forces until assisted in such forceabsorption by the support hook.Iadd., said combined guide and supporthook extending in the circumferential direction of the clamp structureand being integral with the inner band portion over at least nearly itsentire circumferential extent, and said force-engaging surface meansbeing located in the end area of said combined guide and support hookaway from the free end of the inner band portion..Iaddend.
 32. Amechanical connection according to claim 31, wherein said combined guideand support hook is a cold-deformed hook with the force-engaging surfacemeans along the end thereof away from the free end of the inner bandportion.
 33. A mechanical connection according to claim 31, wherein saidcombined guide and support hook is a tab-like member pressed out of theinner band portion and extending generally in the circumferentialdirection of the clamp structure, said force-engaging surface meansbeing formed by the inclined, upwardly extending rear edge of thetab-like member facing away from the free end of the inner band portion.34. A three-partite clamp structure, especially for use in applicationsin which space conditions do not permit any projecting parts, such asplastically deformable ears, which consists of two standard parts and ofa band means of a length depending on the desired diameter of the clampstructure in the installed condition when tightened about an object tobe fastened, characterized in that .[.two.]. .Iadd.the .Iaddend.partsformed by two band portions are operable to be mechanically connectedwith each other in the area of overlap thereof by at least one outwardlyextending hook means in the inner band portion engaging in an aperturemeans in the outer band portion, in that a respective band portion ismechanically connected with the corresponding end of the band means byhook means engaging in aperture means, and in that the inner and outerband portions are provided with tool-engaging means offering substantialresistance in the circumferential direction, whereby clamp structures ofdifferent diameter can be obtained by choosing a suitable length of bandmeans, the tool-engaging means being constituted by cold-deformed,pressed-out portions extending generally in the circumferentialdirection of the clamp structure so that each pressed-out portionremains integral at least on both sides thereof with the respective bandportion and the tool-engaging means are able to withstand substantialforces in the circumferential direction without tearing to permit asecure tightening of the clamp structure about the object to be fastenedby engagement of the hook means in the aperture means without the use ofany other tightening means in the clamp structure.
 35. A clamp structureaccording to claim 34, characterized in that the pressed-outtool-engaging means of the inner and outer band portions are ofcomplementary shape so that the inner pressed-out tool-engaging means isable to slide under the outer pressed-out tool-engaging means duringtightening of the clamp structure.
 36. A clamp structure according toclaim .[.34.]..Iadd.35.Iaddend., characterized in that within each areaof overlap of a band portion and the band means, further means areprovided effectively eliminating any step therebetween near an innerfree end.
 37. A clamp structure according to claim 34, characterized inthat within each area of overlap of a band portion and the band means,further means are provided effectively eliminating any step therebetweennear an inner free end.
 38. A clamp structure according to claim 37,characterized in that the further means includes a tongue-like extensionat each inner end of one of the three parts operable to engage in atongue-receiving means formed at least in part by an outwardly directedstep in the respective overlying band part. .Iadd.39. A mechanicalconnection according to claim 38, characterized in that each bandportion is provided with several hook means, one of said hook meansbeing an outwardly extending preassembly hook adapted to engage in acorresponding aperture means of the band means and being operable to bebent down to hold the respective band portion and band means in apreassembled condition. .Iaddend. .Iadd.40. A mechanical connectionaccording to claim 34, characterized in that each band portion isprovided with several hook means, one of said hook means being anoutwardly extending preassembly hook adapted to engage in acorresponding aperture means of the band means and being operable to bebent down to hold the respective band portion and band means in apreassembled condition..Iaddend. .Iadd.41. A three-partite clampstructure, which consists of a two-partite partial clamp assembly formedby two standard parts and of a band means provided with spaced aperturemeans near each end thereof, the band means being of a length dependingon the desired diameter of the clamp structure in the installedcondition when tightened about an object to be fastened by tighteningmeans provided in the two-partite partial clamp assembly, the two partsbeing operable to be mechanically connected with each other in the areaof overlap thereof by at least two outwardly extending hook means in theinner band portion formed by one of said two parts and operable toengage in corresponding aperture means in the outer band portion formedby the other of said two parts, said hook means providing guide andsupport as well as preassembly functions with at least one hook meansbeing a cold-deformed hook and another hook means being a preassemblyhook which is operable to be bent down to hold the two parts inpreassembled condition, the two parts being provided with further meanseffectively eliminating any step in the area of mutual overlap of thefree end of the inner band portion and of the overlying outer bandportion including a tongue-like extension at the free end of the innerband portion operable to engage in a tongue-receiving means formed atleast in part by an outwardly directed step in the outer band portionand located on the side of the innermost aperture means thereof, each ofthe two parts being operable to be mechanically interconnected with thecorresponding end of the band means by outwardly extending further hookmeans in each band portion operable to engage in corresponding spacedaperture means of the band means, said further hook means providingguide and support as well as preassembly functions with at least onefurther hook means in each band portion being a cold-deformed hook andanother further hook means in each band portion being a preassembly hookwhich is operable to be bent down to hold the corresponding band portionin preassembled condition relative to the overlying free end of the bandmeans, each end of the band means and of the associated end of thecorresponding band portion being provided with still further meanseffectively eliminating any step in the area of mutual overlap includinga tongue-like extension at the associated free end of the correspondingband portion operable to engage in a tongue-receiving means formed atleast in part by an outwardly directed step near the corresponding freeend of the band means whereby a clamp structure of any desired size canbe obtained by utilizing an appropriate length of band means. .Iaddend..Iadd.42. A clamp structure according to claim 41, wherein thetongue-receiving means in the outer band portion is formed by anoutwardly displaced central band portion delimited on both sides bylongitudinal cuts in the outer band portion which defines in effect achannel for receiving therein the tongue-like extension while leavinglateral band portions on both sides of the outwardly displaced centralband portion, whereby the channel extends from the step away from thetightening means in the outer band portion. .Iaddend. .Iadd.43. A clampstructure according to claim 42, wherein the tongue-receiving means neareach end of the band means is formed by an aperture means beginning atleast within the area of the step in the band means and extending awayfrom the corresponding free band end. .Iaddend. .Iadd.44. A clampstructure according to claim 41, wherein the tongue-receiving means neareach end of the band means is formed by an aperture means beginning atleast within the area of the step in the band means and extending awayfrom the corresponding free band end. .Iaddend. .Iadd.45. A clampstructure, especially for use in applications in which space conditionsdo not permit any projecting parts, such as plastically deformable ears,comprising clamping band means having open ends formed by an inner andouter band portion intended to overlap, and means mechanicallyinterconnecting the overlapping open ends of the band means includingoutwardly extending hook means in the inner band portion operable toengage in aperture means in the outer band portion in the installedcondition of the clamp structure, characterized in that the meansmechanically interconnecting the open ends enable tightening of the bandmeans about an object to be fastened and include tool-engaging meansprovided in the inner and outer band portions, said tool-engaging meansbeing formed by pressed-out portions pressed-out of the inner and outerband portions and extending generally in the circumferential directionso that each pressed-out portion remains integral at least on both sidesthereof with the respective band portion, whereby said tool-engagingmeans are able to withstand substantial forces in the circumferentialdirection without tearing which permit a secure tightening of the clampstructure about the object to be fastened without the use of any othertightening means in the clamp structure, and in that the outer bandportion is provided adjacent its pressed-out tool-engaging means with anelongated opening extending in the direction toward the end of the outerband portion and, adjoining said opening, with aperture means receivingsaid hook means, said opening being of such width that the pressed-outtool-engaging means of the inner band portion can extend therethrough..Iaddend. .Iadd.46. A clamp structure according to claim 45,characterized in that the inner band portion including its tool-engagingmeans is located in the installed condition of the clamp structureradially inwardly of the outer band portion within the area between itsaperture means and the tool-engaging means in the outer band portion..Iaddend. .Iadd.47. A clamp structure according to claim 45,characterized in that one of the hook means is a generallycircumferentially extending combined guide and support hook having aforce-engaging surface means located in the area thereof opposite thefree end of the inner band portion. .Iaddend. .Iadd.48. A clampstructure according to claim 47, characterized in that theforce-engaging surface means is of approximately V-shape, as seen inplan view. .Iaddend. .Iadd.49. A clamp structure according to claim 47,characterized in that the force-engaging surface means is formed by arearwardly outwardly slanting surface. .Iaddend. .Iadd.50. A clampstructure according to claim 47, characterized in that only a singlesuch combined guide and support hook is used as the hook means in themeans mechanically interconnecting the overlapping open ends of the bandmeans. .Iaddend. .Iadd.51. A clamp structure according to claim 45,characterized in that said inner band portion is provided with anoutwardly extending hook spaced from the pressed-out tool-engaging meansthereof in the circumferential direction away from the free end thereof,said hook being of such width as to be able to extend through saidopening and upon engagement with the end surface of said openingopposite the tool-engaging means determining a pre-assembly position ofthe two-engaging means. .Iaddend. .Iadd.52. A clamp structure accordingto claim 45, characterized in that the pressed-out tool-engaging meansof the inner and outer band portions are of complementary shape so thatthe inner pressed-out tool-engaging means is able to slide under theouter pressed-out tool-engaging means during tightening of the clampstructure. .Iaddend. .Iadd.53. A clamp structure according to claim 45,wherein the tool-engaging means in the outer band portion is located onthe side of the aperture means opposite the free end of the outer bandportion and the tool-engaging means in the inner band portion is locatedbetween the outwardly extending hook means and the free end of the innerband portion..Iaddend.